Mutation screening of EXT genes in Chinese patients with multiple osteochondromas

Multiple osteochondromas (MO), a dominantly inherited genetic disorder, is characterized by the presence of multiple osteochondromas in the long bones. EXT1 and EXT2 are the causative genes in most MO patients. We have characterized 9 MO families and 1 sporadic case involving a total of 25 patients. The coding exons of EXT1 and EXT2 were screened in 10 probands affected with MO. In five of the 10 probands novel pathogenic mutations have been identified: two in EXT1 and three in EXT2. Four probands carried recurrent mutations and one proband had no detectable mutation. Our study extends the mutational spectrum in EXT1 and EXT2 and will facilitate the deep understanding of the pathophysiology of the disease.     

Novel complex Re-Arrangement of ARG1 commonly shared by unrelated patients with Hyperargininemia

Background

Hyperargininemia is a very rare progressive neurometabolic disorder caused by deficiency of hepatic cytosolic arginase I, resulting from mutations in the ARG1 gene. Until now, some mutations were reported worldwide and none of them were of Southeast Asian origins. Furthermore, most reported mutations were point mutations and a few others deletions or insertions.

Objective

This study aims at identifying the disease-causing mutation in the ARG1 gene of Malaysian patients with hyperargininemia.

Methodology

We employed a series of PCR amplifications and direct sequencing in order to identify the mutation. We subsequently used quantitative real-time PCR to determine the copy number of the exons flanking the mutation. We blasted our sequencing data with that of the reference sequence in the NCBI in order to obtain positional insights of the mutation.

Results

We found a novel complex re-arrangement involving insertion, inversion and gross deletion of ARG1 (designated g.insIVS1 + 1899GTTTTATCAT;g.invIVS1 + 1933_ + 1953;g.delIVS1 + 1954_IVS2 + 914;c.del116_188;p.Pro20SerfsX4) commonly shared by 5 patients with hyperargininemia, each originating from different family. None of the affected families share known relationship with each other, although four of the five patients were known to have first-cousin consanguineous parents.

Conclusion

This is the first report of complex re-arrangement in the ARG1. Further analyses showing that the patients have shared the same geographic origin within the northeastern part of Malaysia prompted us to suggest a simple molecular screening of hyperargininemia within related ethnicities using a long-range PCR.     

Mutational screening of SF1 and WNT4 in Tunisian women with premature ovarian failure

Background

WNT4 and SF1 genes play an important role in ovarian development. They constitute coherent candidate genes associated with premature ovarian failure (POF) pathogenesis.

Methods

We sequenced the coding region of WNT4 and SF1 in 55 Tunisian women with POF and 100 healthy controls.

Results

We identified a synonymous variation in WNT4 (c.99G>A, p.Ser33Ser) and a substitution (c.G437C) in SF1 gene inducing G146 to Ala (GGG–GCG) missense mutation. WNT4 (c.99G>A, p.Ser33Ser) was not associated with POF pathology. However, a positive association of SF1 Gly146Ala polymorphism was noted. Gly146Ala minor allele frequency was significantly higher (p = 0.029) in POF patients versus controls and Ala allele containing genotypes (p = 0.005) were positively associated with POF pathology. The carriage of 146Ala allele was also associated with a significant reduction in estradiol plasma levels.

Conclusions

SF1 Gly146Ala polymorphism seems to be associated with POF pathology in the Tunisian population likely by reducing estradiol levels.     

Potential role for Ext1-dependent heparan sulfate in regulating P311 gene expression in A549 carcinoma cells

Background

Exostosin-1 (EXT1), a member of the EXT protein family, is indispensable for synthesis of heparan sulfate (HS) chains that bind to and modulate the signaling efficiency of numerous growth factor activities. We have previously shown that Ext1 mutated mouse embryonic fibroblasts produce short sulfated HS chains which dramatically influence tumor cell behavior in a 3-dimensional (3D) heterospheroid system composed of tumor cells and fibroblasts.

Exome sequencing identifies RDH12 compound heterozygous mutations in a family with severe retinitis pigmentosa

Objective

Retinitis pigmentosa (RP) is the most prevalent type of inherited retinal degeneration and one of the commonest causes of genetically determined visual dysfunction worldwide. To date, approximately 35 genes have been associated with nonsyndromic autosomal recessive RP (arRP), however the small contribution of each gene to the total prevalence of arRP and the lack of a clear genotype–phenotype correlation complicate the genetic analysis in affected patients. Next generation sequencing technologies are powerful and cost-effective methods for detecting causative mutations in both sporadic and familial RP cases.

Methods

A Mexican family with 5 members affected from arRP was studied. All patients underwent a complete ophthalmologic examination. Molecular methods included genome-wide SNP homozygosity mapping, exome sequencing analysis, and Sanger-sequencing confirmation of causal mutations.

Results

No regions of shared homozygosity among affected subjects were identified. Exome sequencing in a single patient allowed the detection of two missense mutations in the RDH12 gene: a c.446T>C transition predicting a novel p.L149P substitution, and a c.295C>A transversion predicting a previously reported p.L99I replacement. Sanger sequencing confirmed that all affected subjects carried both RDH12 mutations.

Conclusions

This study adds to the molecular spectrum of RDH12-related retinopathy and offers an additional example of the power of exome sequencing in the diagnosis of recessively inherited retinal degenerations.     

Effects of passive smoking on breast cancer risk in pre/post-menopausal women as modified by polymorphisms of PARP1 and ESR1

Objectives

The association between passive smoking and breast cancer risk differs in pre- and post-menopausal women. We aimed to explore the modification effects of PARP1 rs1136410 and ESR1 rs2234693 on the association between passive smoking and breast cancer risk among pre- and post-menopausal women.

Design and methods

A case–control study of 839 breast cancer cases and 863 controls was conducted. The gene–environment interactions were tested after adjusting for potential breast cancer risk factors with unconditional logistic regression models.

Results

We found that the effect of passive smoking was modified by the genotypes in both pre- and post-menopausal women, but in opposite directions. The combination of the TC/CC genotypes of ESR1 rs2234693 and passive smoking significantly increased the risk of breast cancer [OR (95%CI): 2.06 (1.39–3.05)] in pre-menopausal women. A significant association was observed between TT genotype and passive smoking [OR (95%CI): 2.40 (1.27–4.53)] in postmenopausal women. For PARP1 rs1136410, similar differential associations were observed, but the interactions were not significant.

Conclusions

These results imply that the risk of breast cancer from passive smoking may be influenced by genetic factors, and that the association may differ depending on menopausal status.     

SLC45A2 mutation frequency in Oculocutaneous Albinism Italian patients doesn't differ from other European studies

Background

Oculocutaneous Albinism (OCA) is a heterogeneous group of inherited diseases involving hair, skin and eyes. To date, six forms are recognized on the effects of different melanogenesis genes.OCA4 is caused by mutations in SLC45A2 showing a heterogeneous phenotype ranging from white hair, blue irides and nystagmus to brown/black hair, brown irides and no nystagmus. The high clinic variety often leads to misdiagnosis.Our aim is to contribute to OCA4 diagnosis defining SLC45A2 genetic variants in Italian patients with OCA without any TYR, OCA2 and TYRP1 gene defects.

Materials and methods

After the clinical diagnosis of OCA, all patients received genetic counseling and genetic test. Automatic sequencing of TYR, OCA2, and TYRP1 genes was performed on DNA of 117 albino patients. Multiplex Ligation-dependent Probe Amplification (MLPA) was carried out on TYR and OCA2 genes to increase the mutation rate. SLC45A2 gene sequencing was then executed in the patients with a single mutation in one of the TYR, OCA2, TYRP1 genes and in the patients, which resulted negative at the screening of these genes.

Results

SLC45A2 gene analysis was performed in 41 patients and gene alterations were found in 5 patients. Four previously reported SLC45A2 mutations were found: p.G100S, p.W202C, p.A511E and c.986delC, and three novel variants were identified: p.M265L, p.H94D, and c.1156+1G>A. All the alterations have been detected in the group of patients without mutations in the other OCA genes.

Conclusions

Three new variants were identified in OCA4 gene; the analysis allowed the classification of a patient previously misdiagnosed as OA1 because of skin and hair pigmentation presence. The molecular defects in SLC45A2 gene represent the 3.4% in this cohort of Italian patients, similar to other Caucasian populations; our data differ from those previously published by an Italian researcher group, obtained on a smaller cohort of patients.     

A CRYGC gene mutation associated with autosomal dominant pulverulent cataract

Purpose

To describe at molecular level a family with pulverulent congenital cataract associated with a CRYGC gene mutation.

Methods

One family with several affected members with pulverulent congenital cataract and 230 healthy controls were examined. Genomic DNA from leukocytes was isolated to analyze the CRYGA-D cluster, CX46, CX50 and MIP genes through high-resolution melting curve and DNA sequencing.

Results

DNA sequencing in the affected members revealed the c.143G>A mutation (p.R48H) in exon 2 of the CRYGC gene; 230 healthy controls and ten healthy relatives were also analyzed and none of them showed the c.143G>A mutation. No other polymorphisms or mutations were found to be present.

Conclusion

In the present study, we described a family with pulverulent congenital cataract that segregated the c.143G>A mutation (p.R48H) in the CRYGC gene. A few mutations have been described in the CRYGC gene in autosomal dominant cataract, none of them with pulverulent cataract making clear the clinical heterogeneity of congenital cataract. This mutation has been associated with the phenotype of congenital cataract but also is considered an SNP in the NCBI data base. Our data and previous report suggest that p.R48H could be a disease-causing mutation and not an SNP.     

Impact of genetic variants of IL-6, IL6R, LRP5, ESR1 and SP7 genes on bone mineral density in postmenopausal Mexican-Mestizo women with obesity

Background

Since obesity and osteoporosis present a high genetic predisposition and polymorphisms of IL-6, IL6R, LRP5, ESR1 and SP7 may influence the risk of both diseases, the aim of this study was to analyze the possible association of polymorphisms in these genes, as well as their haplotypes, with BMD variations in postmenopausal Mexican-Mestizo women with grade 2 or grade 3 obesity.

Methods

One hundred eighty unrelated postmenopausal women with grade 2 or grade 3 obesity were included. BMD was measured in total hip and lumbar spine by dual-energy X-ray absorptiometry. DNA was obtained from blood leukocytes. Rs1800795 of IL-6, rs2228145 of IL6R, rs3736228 of LRP5, rs9340799 (XbaI) and rs2234693 (PvuII), of ESR1, rs10876432 and rs2016266, of SP7 (and their haplotypes), were studied by real-time PCR allelic discrimination. Deviations from Hardy–Weinberg equilibrium were tested. Pairwise linkage disequilibrium between single nucleotide polymorphisms was calculated by direct correlation r², and haplotype analysis was conducted.

Results

Using WHO criteria, 54.5% had grade 2 obesity, and 45.5% had grade 3 obesity. Regarding DXA results, 11.1% women had osteoporosis, 41.7% had osteopenia, and 47.2% had normal BMD. Genotype and haplotype analysis showed no significant differences with BMD variations at the lumbar spine, total hip or femoral neck.

Conclusions

We did not find a significant association between the polymorphisms analyzed or their haplotypes and BMD variations in postmenopausal women with obesity. The higher BMD observed in women with obesity could be the result of an adaptive response to the higher loading of the skeleton.     

Different activities of the conserved lysine residues in the double-stranded RNA binding domains of RNA helicase A in vitro and in the cell

Background

RNA helicase A regulates a variety of RNA metabolism processes including HIV-1 replication and contains two double-stranded RNA binding domains (dsRBD1 and dsRBD2) at the N-terminus. Each dsRBD contains two invariant lysine residues critical for the binding of isolated dsRBDs to RNA. However, the role of these conserved lysine residues was not tested in the context of enzymatically active full-length RNA helicase A either in vitro or in the cells.

Methods

The conserved lysine residues in each or both of dsRBDs were substituted by alanine in the context of full-length RNA helicase A. The mutant RNA helicase A was purified from mammalian cells. The effects of these mutations were assessed either in vitro upon RNA binding and unwinding or in the cell during HIV-1 production upon RNA helicase A–RNA interaction and RNA helicase A-stimulated viral RNA processes.

Results

Unexpectedly, the substitution of the lysine residues by alanine in either or both of dsRBDs does not prevent purified full-length RNA helicase A from binding and unwinding duplex RNA in vitro. However, these mutations efficiently inhibit RNA helicase A-stimulated HIV-1 RNA metabolism including the accumulation of viral mRNA and tRNA^Lys3 annealing to viral RNA. Furthermore, these mutations do not prevent RNA helicase A from binding to HIV-1 RNA in vitro as well, but dramatically reduce RNA helicase A–HIV-1 RNA interaction in the cells.

Conclusions

The conserved lysine residues of dsRBDs play critical roles in the promotion of HIV-1 production by RNA helicase A.

General significance

The conserved lysine residues of dsRBDs are key to the interaction of RNA helicase A with substrate RNA in the cell, but not in vitro.     

GSTM1, GSTT1, GSTP1, and GSTA1 genetic variants are not associated with coronary artery disease in Taiwan

Background and objective

The genetic variants of xenobiotic-metabolizing enzymes, such as those encoded by glutathione-S-transferase (GST) genes, may be associated with the risk of coronary artery disease (CAD). To investigate the genetic factors for CAD, we examined the GSTM1, GSTT1, GSTP1, and GSTA1 genotypes in a CAD cohort in Taiwan.

Methods

Our study included 458 CAD participants and 209 control participants who received coronary angiography to assess CAD. The severity of CAD was defined as the number of coronary vessels with 50% or greater stenosis. Sequence variation of the GSTM1 and GSTT1 genes was determined using a polymerase chain reaction (PCR). The GSTP1 (Ile105Val), and GSTA1 (-69C > T) genetic variants were identified using a combination of PCR and restriction fragment length polymorphism analysis. Logistic regression analysis was used to calculate the odds ratios (ORs) and 95% confidence intervals.

Results

Among the GST genetic variants examined, the GSTT1 null genotype was more prevalent in CAD participants with 3 stenosed vessels than in control participants (OR = 1.64, P = .02). This association was no longer observed after adjusting for age, sex, smoking, alcohol use, diabetes mellitus, and serum levels of total cholesterol and high-density lipoprotein cholesterol (OR = 1.28, P = .40). Both univariate and multivariate logistic regression analyses found no significant associations between CAD and the other genetic variants, either separately or in combination. In addition, no effects of interactions between the genotypes and environmental factors, such as cigarette smoking, were significantly associated with the risk of CAD.

Conclusion

The GST genetic variants examined were not associated with susceptibility to CAD in our Taiwanese cohort. This null association requires further confirmation with larger samples.     

Three novel homozygous mutations in the GNPTG gene that cause mucolipidosis type III gamma

Background

Mucolipidosis type III gamma (MLIII gamma) is an autosomal recessive disease caused by a mutation in the GNPTG gene, which encodes the γ subunit of the N-acetylglucosamine-1-phosphotransferase (GlcNAc-1-phosphotransferase). This protein plays a key role in the transport of lysosomal hydrolases to the lysosome.

Methods

Three Chinese children with typical skeletal abnormalities of MLIII were identified, who were from unrelated consanguineous families. After obtaining informed consent, genomic DNA was isolated from the patients and their parents. Direct sequencing of the GNPTG and GNPTAB genes was performed using standard PCR reactions.

Results

The three probands showed clinical features typical of MLIII gamma, such as joint stiffness and vertebral scoliosis without coarsened facial features. Mutation analysis of the GNPTG gene showed that three novel mutations were identified, two in exon seven [c.425G>A (p.Cys142Val)] and [c.515dupC (p.His172Profs27X)], and one in exon eight [c.609+1G>C]. Their parents were determined to be heterozygous carriers when compared to the reference sequence in GenBank on NCBI.

Conclusions

Mutation of the GNPTG gene is the cause of MLIII gamma in our patients. Our findings expand the mutation spectrum of the GNPTG gene and extend the knowledge of the phenotype–genotype correlation of the disease.     

Production of fully assembled and active Aquifex aeolicus F1FO ATP synthase in Escherichia coli

Background

F₁F_O ATP synthases catalyze the synthesis of ATP from ADP and inorganic phosphate driven by ion motive forces across the membrane. A number of ATP synthases have been characterized to date. The one from the hyperthermophilic bacterium Aquifex aeolicus presents unique features, i.e. a putative heterodimeric stalk. To complement previous work on the native form of this enzyme, we produced it heterologously in Escherichia coli.

Methods

We designed an artificial operon combining the nine genes of A. aeolicus ATP synthase, which are split into four clusters in the A. aeolicus genome. We expressed the genes and purified the enzyme complex by affinity and size-exclusion chromatography. We characterized the complex by native gel electrophoresis, Western blot, and mass spectrometry. We studied its activity by enzymatic assays and we visualized its structure by single-particle electron microscopy.

Results

We show that the heterologously produced complex has the same enzymatic activity and the same structure as the native ATP synthase complex extracted from A. aeolicus cells. We used our expression system to confirm that A. aeolicus ATP synthase possesses a heterodimeric peripheral stalk unique among non-photosynthetic bacterial F₁F_O ATP synthases.

Conclusions

Our system now allows performing previously impossible structural and functional studies on A. aeolicus F₁F_O ATP synthase.

General significance

More broadly, our work provides a valuable platform to characterize many other membrane protein complexes with complicated stoichiometry, i.e. other respiratory complexes, the nuclear pore complex, or transporter systems.     

CHK2 1100delC,IVS2 + 1G>A and I157T mutations are not present in hepatocellular cancer cases from a Turkish population

Aim

The cell cycle checkpoint kinase 2 (CHK2) protein participates in the DNA damage response in many cell types. Germline mutations in CHK2 (1100delC, IVS2 + 1G>A and I157T) have been associated with a range of cancer types. This study aimed to investigate whether CHK2 1100delC, IVS2 + 1G>A and I157T mutations play an important role in the development of hepatocellular carcinoma (HCC) in a Turkish population.

Methods

A total of 165 hepatocellular cancer cases and 446 cancer-free controls were genotyped for CHK2 mutations by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and allele specific-polymerase chain reaction (AS-PCR) methods.

Results

We did not find CHK2 1100delC, IVS2 + 1G>A and I157T mutations in any of 611 Turkish subjects.

Conclusion

Our results demonstrate for the first time that CHK2 1100delC, IVS2 + 1G>A and I157T mutations have not been a genetic susceptibility factor for HCC in the Turkish population. Overall, our data suggests that genotyping of CHK2 mutations in clinical settings in the Turkish population should not be recommended. Independent studies are needed to validate our findings in a larger series, as well as in patients of different ethnic origins.     

Novel insertion mutation p.Asp610GlyfsX23 in APC gene causes familial adenomatous polyposis in Chinese families

Objective

The aim of the study was to identify the causative gene defects associated with familial adenomatous polyposis (FAP) in two Chinese pedigrees.

Methods

The diagnosis of FAP patients was confirmed by clinical manifestations, family histories, colonoscopy and pathology examinations. Blood samples were collected and genomic DNA was extracted. The mutation analysis of the adenomatous polyposis coli (APC) and human mutY homolog (MUTYH) genes was conducted by direct polymerase chain reaction (PCR) sequencing and multiplex ligation-dependent probe amplification (MLPA).

Results

In pedigree A, the results of direct PCR sequencing revealed a heterozygous insertion mutation at codon 610 in exon 15 of APC gene (c.1828_1829insG), which resulted in frameshift change (p.Asp610GlyfsX23) in all 4 patients, but was absent in the unaffected familial members and controls. In pedigree B, we didn't identify that causative mutations cosegregated with the clinical phenotype in the APC and MUTYH genes.

Conclusions

We identified a novel insertion mutation as the pathogenic gene of FAP in Chinese population, which could enrich the germline mutation spectrum of APC gene, and the prophylactic proctocolectomy for the mutation carrier in family should be considered.     

Novel UMOD mutations in familial juvenile hyperuricemic nephropathy lead to abnormal uromodulin intracellular trafficking

Background

Familial juvenile hyperuricemic nephropathy (FJHN) is an autosomal dominant disorder characterized by hyperuricemia and progressive chronic kidney disease. Uromodulin gene (UMOD) mutations, leading to abnormalities of uromodulin intracellular trafficking contribute to the progress of the disease.

Methods

We did UMOD screening in three Chinese FJHN families. We thus constructed mutant uromodulin express plasmids by site-mutagenesis from wild type uromodulin vector and transfected them into HEK293 (human embryonic kidney) cells. And then we detected uromodulin expression by western blot and observed intracellular distribution by immunofluorescence.

Results

We found three heterozygous mutations. Mutation Val109Glu (c.326T/A; p.Val109Glu) and mutation Pro236Gln (c.707C/A; p.Pro236Gln) were newly indentified mutations in two distinct families (family F1 and family F3). Another previously reported UMOD mutation Cys248Trp (c.744C/G; p.Cys248Trp) was detected in family F2. Phenotypes varied both within the same family and between different families. Uromodulin expression is abnormal in the patient biopsy. Functional analysis of mutation showed that mutant types of uromodulin were secreted into the supernatant medium much less when compared with wild type. In mutant type uromodulin transfected cells, intracellular uromodulin localized less in the Golgi apparatus and more in endoplasmic reticulum(ER).

Conclusions

Our results suggested that the novel uromodulin mutations found in the Chinese families lead to misfolded protein, which was retained in the endoplasmic reticulum, finally contributed to the phenotype of FJHN.     

Proteome and phosphoproteome analysis of the serine/threonine protein kinase E mutant of Mycobacterium tuberculosis

Aims

Serine/threonine protein kinases (STPKs) have prominent roles in the survival mechanisms of Mycobacterium tuberculosis (M. tuberculosis). Previous studies from our laboratory underscored the role of PknE, an STPK in virulence, adaptation and the suppression of host cell apoptosis. In this study, two-dimensional gel electrophoresis was used to study the proteome and phosphoproteome profiles of wild type M. tuberculosis and its isogenic pknE deletion mutant (ΔpknE) during growth in Middlebrook 7H9 and nitric oxide stress.

Main methods

Wild-type M. tuberculosis and its isogenic pknE deletion mutant strain were grown in Middlebrook 7H9 as well as subjected to nitric oxide stress using sodium nitroprusside. Whole cell lysates were prepared and analyzed by 2D-gel electrophoresis. Phosphoproteomes were analyzed using phospho serine and phospho threonine antibodies after subjecting the 2D-gels to western blotting. Proteins of interest were identified using mass spectrometry.

Key findings

Our analysis provides insights into the targets that impose pro-apoptotic as well as altered cellular phenotypes on ΔpknE, revealing novel substrates and functions for PknE.

Significance

For the first time, our proteome and phosphoproteome data decipher the function of PknE in cell division, virulence, dormancy, suppression of sigma factor B and its regulated genes, suppression of two-component systems and in the metabolic activity of M. tuberculosis.     

Formaldehyde induces hyperphosphorylation and polymerization of Tau protein both in vitro and in vivo

Background

Chronic formaldehyde exposure leads to memory impairment and abnormal elevation of endogenous formaldehyde has been found in the brains of Alzheimer's disease (AD) patients. Hyperphosphorylated Tau protein with subsequent aggregates as neurofibrillary tangles (NFTs) is one of the typical pathological characteristics in AD brains. The mechanism underlying abnormally elevated concentrations of endogenous formaldehyde that induce Tau hyperphosphorylation is unknown.

Methods

N2a cells and mice were treated with formaldehyde for different time points, then Western blotting and immunocytochemistry were utilized to determine the phosphorylation and polymerization of Tau protein. HPLC was used to detect the concentration of formaldehyde in cell media.

Results

Under formaldehyde stress, Tau became hyperphosphorylated, not only in the cytoplasm, but also in the nucleus of neuroblastoma (N2a) cells, and mouse brains. Polymers of cellular phospho-Tau were also detected. Significant accumulation of glycogen synthase kinase-3β (GSK-3β) in the nucleus of N2a and mouse brain cells, and elevation of its phosphorylation at Y216, was observed under formaldehyde stress. Formaldehyde-induced Tau hyperphosphorylation was blocked in the presence of LiCl and CT99021, inhibitors of GSK-3β, and by RNAi interference.

Conclusions

Formaldehyde, which may cause age-related memory loss, can act as a factor triggering Tau hyperphosphorylation via GSK-3β catalysis and induces polymerization of Tau.

General significance

Investigation of formaldehyde-induced Tau hyperphosphorylation may provide novel insights into mechanisms underlying tauopathies.     

Secretoglobin 1A member 1 (SCGB1A1) + 38A/G polymorphism is associated with asthma risk: A meta-analysis

Background

Epidemiological studies have evaluated the association between Secretoglobin 1A member 1 (SCGB1A1) + 38A/G polymorphism and asthma, but the results remain inconclusive. The aim of this study was to perform a meta-analysis to investigate a more authentic association between SCGB1A1 + 38A/G polymorphism and asthma.

Methods

Published literature from PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), and Embase databases were searched for eligible publications. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using random or fixed-effect model according the between-study heterogeneity.

Results

A total of 19 case-control studies in 18 articles were included in the meta-analysis, including 3191 cases and 5182 controls. We found that SCGB1A1 + 38A/G polymorphism was associated with a significantly increased risk of asthma risk when all studies were pooled in a dominant model (OR = 1.29; 95% CI 1.08–1.54; P = 0.005). The cumulative meta-analysis and sensitivity analysis further strengthened the stability of the result. Furthermore, publication bias was not detected.

Conclusions

This study suggested that SCGB1A1 + 38A/G polymorphism was a risk factor for asthma. Further large and well-designed studies are needed to confirm this association.     

Identification and characterization of retinoid-active short-chain dehydrogenases/reductases in Drosophila melanogaster

Background

In chordates, retinoid metabolism is an important target of short-chain dehydrogenases/reductases (SDRs). It is not known whether SDRs play a role in retinoid metabolism of protostomes, such as Drosophila melanogaster.

Methods

Drosophila genome was searched for genes encoding proteins with ∼ 50% identity to human retinol dehydrogenase 12 (RDH12). The corresponding proteins were expressed in Sf9 cells and biochemically characterized. Their phylogenetic relationships were analyzed using PHYLIP software.

Results

A total of six Drosophila SDR genes were identified. Five of these genes are clustered on chromosome 2 and one is located on chromosome X. The deduced proteins are 300 to 406 amino acids long and are associated with microsomal membranes. They recognize all-trans-retinaldehyde and all-trans-3-hydroxyretinaldehyde as substrates and prefer NADPH as a cofactor. Phylogenetically, Drosophila SDRs belong to the same branch of the SDR superfamily as human RDH12, indicating a common ancestry early in bilaterian evolution, before a protostome–deuterostome split.

Conclusions

Similarities in the substrate and cofactor specificities of Drosophila versus human SDRs suggest conservation of their function in retinoid metabolism throughout protostome and deuterostome phyla.

General significance

The discovery of Drosophila retinaldehyde reductases sheds new light on the conversion of β-carotene and zeaxantine to visual pigment and provides a better understanding of the evolutionary roots of retinoid-active SDRs.